1. Field of the Invention
The invention relates to modified, solid carriers to immobilize biomolecules, e.g. proteins, and a process to bind proteins.
2. Discussion of the Background
The immobilization of biologically significant proteins on carriers represents an excellent instrument both in biochemical research and in biotechnology (cf. Ullmann's Encyclopedia of Industrial Chemistry, 5th ed., vol. A14, pp. 2-42, VCH 1989).
To date, suitable solid organic matrix materials have been primarily (modified) polysaccharides, proteins and active carbon from natural sources, synthetic polymers such as polystyrene, poly(meth)acrylates, polyacrylamides, maleic anhydride polymers, vinyl and allyl polymers and polyamides. Suitable inorganic carriers are minerals, in particular clay materials, diatomaceous earth and talcum as well as synthetic materials such as glass, metal oxides and metals. Of the possible types of fixation to the matrix, covalent bonding is preferred for the activity determining structures of the biologically active substances that are to be fixed into position. The active substances are predominantly proteins. The carrier materials themselves usually do not have any reactive groups in order to link them to the active groups of the proteins (especially amino, hydroxyl or phenol, amide, thiol, carboxyl groups), but rather they require activation. To activate the carrier materials a range of reactive groups have been introduced. For example, groups that produce an alkylation or acylation of free amino, phenol and/or thiol groups of the biologically active proteins (cf. Ullmann's Encyclopedia, loc. cit., U.S. Pat. No. 4,829,101; CA-A 1,212,058). This group includes, e.g., the polymer-bonded chloro-s-triazinyl group, which, primarily bonded to cellulose, serves to directly couple the proteins (cf. B. P. Surinev et al., Biokhimiya, 31, 387 (1966); G. Kay et al., Nature, 216 (1967), 514; Biochim. Biophys. Acta, 198, (1970), 276).
A carrier system that is commercially available is the cross-linked copolymer comprising acrylamide or methacrylamide and glycidyl acrylate or glycidyl methacrylate and/or allyl glycidyl ether, which is made preferably of bead-shaped particles. Such matrix polymers are specified in the DE-C 27 22 751, U.S. Pat. No. 4,190,713 and U.S. Pat. No. 4,511,694. The epoxy functions of such a carrier system can be condensed directly with nucleophilic groups on the protein surface, however, they can also be linked as bifunctional reagents by means of dicarboxylic acid bishydrazides. (GB-A 2,212,500). Of significant practical interest are also membrane matrix materials as carriers of biologically active proteins, in particular immunologically relevant proteins or enzymes.